Backgrounds and objective Since the discovery of X-rays by Conrad Rontgen in 1895,almost all the practical uses of radiography for human imaging have been based on X-ray absorbtion contrast and optic geometric.

• 研究背景和目的 自Rontgen1895年发现X射线以来，常规X射线成像技术都是建立在吸收衬度和几何光学基础上。